23 research outputs found

    Analysis of Microwave Heating Process for Demulsification of Water-in-Crude Oil Emulsions

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    In this investigation, the process of microwave heating technology was evaluated to measure the effect of some important parameters such as dielectric properties (έ and ɛʺ), rate of temperature increase (dT/dt), volume rate of heat generation (Qmw), wavelength (λ) and penetration depth (Dp) during the microwave irradiation on crude oil emulsions. Two types of Malaysian crude oil mixed together at a volume ratio of 50-50% and applied for further investigations. In order to ensure the efficiency of the process, the improvement of existing techniques and the development of new technology different ratios of water and oil were utilized to prepare the emulsions of water-in-crude oil (W/O). The emulsion samples were heated under 360 watt and 540 watt for 3 to 5 minutes. The findings of the microwave heating demulsification showed that higher microwave power (540 watt) along with the radiation time (5 min) were not much effective for water separation. This is because of the over boiling of the samples. Consequently, for microwave heating demulsification the best water separation efficiency was achieved at 3 (minutes), 360 (watt). Based on the result of microwave parameter’s calculations, it was found that parameters such as; dT/dt, Qmw, έ and ɛʺ, were inversely proportional to the radiation time. However, parameters such as λ and Dp were directly proportional to the time of the radiation

    Effect of co2 partial pressure on dry reforming of ethanol for hydrogen production

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    The effect of CO2 partial pressure on ethanol dry reforming was evaluated over 5%Ce-10%Co/Al2O3 catalyst at = PCO2 = 20-50 kPa, PC2H5OH = 20 kPa, reaction temperature of 973 K under atmospheric pressure. The catalyst was prepared by using impregnation method and tested in a fixed-bed reactor. X-ray diffraction measurements studied the formation of Co3O4, spinel CoAl2O4 and CeO2, phases on surface of 5%Ce-10%Co/Al2O3 catalyst. CeO2, CoO and Co3O4 oxides were obtained during temperature–programmed calcination. Ce-promoted 10%Co/Al2O3 catalyst possessed high BET surface area of 137.35 m2 g-1. C2H5OH and CO2 conversions was improved with increasing CO2 partial pressure from 20-50 kPa whilst the optimal selectivity of H2 and CO was achieved at 50 kPa

    Iridoids of fenugreek (Trigonella-foenum-graecum L.) seed extract detected via LC-QTOF-MS analysis

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    Fenugreek seed is a traditional medicinal plant with a wide biological activity. In this study, iridoids (Asperulosidic acid (1), 7-O-Methylmorroniside (2), Gentiopicroside (3), Rehmannioside A (4), Loganic acid-6′-O-β-Dglucoside (5), Sweroside (6), Penstemoside (7), 6′-O-β-D-Glucosyl Gentiopicroside (8), Oleuropein (9)) in optimized microwave-assisted extract of fenugreek seed were detected for the first time. The identification of iridoid compounds was carried out by liquid chromatography quadrupole time-of-flight mass spectrometry coupled with electrospray ionization (LC-QTOF-MS-ESI) in positive ion modes and Fourier Transform Infrared Spectroscopy (FTIR) analysis. More than 400 compounds were detected via LC-QTOF-MS, while among them only 9 were iridoids. The presence of iridoid compounds was also confirmed with FTIR analysis. In positive ion mode, iridoids with formic acid as mobile phase associated in formation of three adducts [+ H, + Na + K]. However, in the case of negative ion no iridoid compound was observed in the extract

    Oxidative ethanol dry reforming for production of syngas over Co-based catalyst : Effect of reaction temperature

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    Till date, oxidative ethanol steam reforming use Ni-based catalysts to produce syngas. However, Ni catalysts suffer from easy deactivation due to the coke formation at low temperatures. Therefore, oxidative ethanol dry reforming is a promising method and was investigated over 10 %Co/Al2O3 catalyst due to their high activity and stability to produce high-quality syngas. More importantly, the syngas can be upgraded to produce liquid biofuels and chemicals. The catalyst was evaluated in a quartz fixed-bed reactor under atmospheric pressure at PCO2 =PO2= 5 kPa, PC2H5OH = 15 kPa, with reaction temperature ranging between 773 and 973 K. The γ-Al2O3 support and 10 %Co/Al2O3 catalyst had BET surface areas of 175.2 m2 g−1 and 143.1 m2 g−1, respectively. Co3O4 and spinel CoAl2O4 phases were detected through X-ray diffraction measurements on the 10 %Co/Al2O3 catalyst surface. H2-TPR measurements indicate that the 10 %Co/Al2O3 catalyst was completely reduced at a temperature beyond 1000 K. NH3-TPD measurements indicated the presence of the weak, medium, and strong acid sites on the γ-Al2O3 support and 10 %Co/Al2O3 catalyst. Due to increased reaction temperature from 773 to 973 K, C2H5OH and CO2 conversions improved from 22.5 % to 93.6 % and 16.9–52.8 %, respectively. Additionally, the optimal yield of H2 and CO obtained at 68.1 % and 58.3 %, respectively. Temperature-programmed oxidation experiments indicated that the amount of carbon deposition was the lowest (28,92 %) at 973 K and increased by 41.48 % at 773 K.publishedVersionPeer reviewe

    Syngas production from ethanol dry reforming over La and Ce promoted Co/Al2O3 catalysts

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    Ethanol dry reforming has been emerged as a promising route for converting the renewable ethanol and undesirable greenhouse gas (CO2) to industrially recognized syngas. It can also be used as feedstock for downstream methanol production and Fischer-Tropsch synthesis. However, the carbonaceous deposition during ethanol dry reforming process leads to deactivation of the catalyst. Therefore, the Co-based catalysts were prepared with La and Ce promoters using a wet impregnation method and investigated the physicochemical attributes of 10%Co/Al2O3 as well as evaluated the effect of operating parameters on the catalytic activity of ethanol dry reforming reaction in a quartz fixed-bed reactor. In addition, the effect of different ceria loading (from 2% to 5%) was evaluated for ethanol dry reforming reaction at 973 K and stoichiometric conditions. The results revealed that the 3% Ce-promoted catalyst showed the highest activity and resistance from coke deposition. The 3%Ce-promoted catalyst was compared with 3%La-promoted and unpromoted catalyst at different C2H5OH:CO2 ratios of 2.5:1-1:2.5 and reaction temperature of 923 to 973 K. The 3%La over bare 10%Co/Al2O3 significantly improved the metal dispersion (about 16.6%) and degree of reduction (98.3%). Besides, C2H5OH and CO2 conversions increased up to 150.6% and 55.5%, respectively with growing reaction temperature from 923 to 973 K due to the endothermic character of ethanol dry reforming reaction. In addition, both reactant conversions increased with rising CO2 partial pressure from 20 to 50 kPa for all catalysts while, the decreasing reactant conversions with increasing C2H5OH partial pressure. In ethanol dry reforming runs, H2/CO ratio was always higher than unity due to the presence of side reaction (ethanol dehydrogenation). Irrespective of reaction conditions, La-promoted catalyst seemed to be the best catalyst in terms of both C2H5OH and CO2 conversions. Reactant conversions of catalysts increased in the order; 10%Co/Al2O3 < 3%Ce-10%Co/Al2O3 < 3%La-10%Co/Al2O3 catalysts for all operating conditions. The 10%Co/Al2O3 and 3%La-10%Co/Al2O3 catalysts were examined for longevity tests in ethanol dry reforming and showed that the 3%La-10%Co/Al2O3 catalyst exhibited the high catalytic activity than that of unpromoted catalyst at stoichiometric condition for 72 h and 973 K. Furthermore, La-promoted catalyst was regenerated with three cycles and plotted with time-on-stream at stoichiometric feed composition for 90 h and T = 973 K. The results found that the 3%La exhibited the highest catalytic performance in terms of activity and carbon deposition compared to the counterpart unpromoted catalyst. The heterogeneous nature of deposited carbons (carbon nanofilament and graphite) on spent catalyst surface was evident spent catalyst characterizations. Additionally, the 3% La promoter reduced the carbon formation from 51.49% to 30.06%. Furthermore, from the power law expression found that the activation energy for Ce- and La-promoted catalysts (about 98 kJ mol-1 and La-promoted 93 kJ mol-1, respectively) was smaller compared to unpromoted 10%Co/Al2O3 catalyst (about 108 kJ mol-1). The Langmuir-Hinshelwood rate expressions also suggested that both reactants (C2H5OH and CO2) were associatively adsorbed on single-site of catalyst with corresponding activation energy of about 106 kJ mol-1. This study suggests that the syngas produced over Co-based catalysts with desirable H2/CO ratios could be used directly in Fischer-Tropsch synthesis without the requirement of adjusting feedstock composition

    The Influence of Process Parameters on Stability Of Water-In-Crude Oil Emulsion Stabilized by Span 80

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    There is a wide range of scientific literature related to emulsion stability, most of them dealt with water-in-oil (W/O) or oil-in-water (O/W) type. The present work is aimed to investigate the stability mechanisms of water-in-crude oil emulsion stabilized by a non-ionic emulsifier (Span 80). The blending of (50-50 vol. %) heavy and light crude oil was first characterized in terms of physico-chemical properties. The emulsion was stabilized by (1.5 and 2.5 vol. %) emulsifier at different water: oil ratio of (20-80 vol. %) and (40-60 vol. %). According to the result of microscopy images, the steric stability was obtained in low water volume fraction content (20%), with the smaller droplet sizes and at higher surfactant concentration (2.5%). The emulsions stabilized with Span 80 obtained a visually stable emulsion in both concentrations of emulsifier and volume fractions of dispersed phase (water) in a period of one week,and there was no water separation was observed in this period. To determine the dynamic viscosity rate, the temperature was varied from 30 ºC to 90 ºC and shear rate from (17 to 85)1/sec respectively. Moreover, the emulsion with the higher water volume fraction (40%) and emulsifier concentration of 2.5 % indicated higher dynamic viscosity.However, in all types of the samples, the dynamic viscosity decreased by increasing the shear rate. The results obtained in this study have exposed the capability of the chosen emulsifier as another promising method for stabilizing w/o emulsions. Further works are, nevertheless, required to provide deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industr

    Influence of CO2 Partial Pressure on Ethanol Dry Reforming Using 5%Ce-10%Co/Al2O3 Catalyst for Hydrogen Production

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    The influence of CO2 partial pressure on ethanol dry reforming has been studied over Ce-promoted Co catalyst supported on Al2O3 from 20 to 50 kPa, C2H5OH was kept at 20 kPa and under atmospheric pressure. The catalyst was synthesized using wet impregnation method and tested in a quartz fixed-bed reactor. X-ray diffraction analysis indicated the formation of CeO2, Co3O4 and spinel CoAl2O4 phases on catalyst surface. CoO and Co3O4 and CeO2 phases were formed during temperature–programmed calcination and 5%Ce-10%Co/Al2O3 catalyst has a total high surface area of 137.35 m2 g-1. Both C2H5OH and CO2 conversions was improved with increasing CO2 partial pressure from 20 at 50 kPa and an optimal selectivity of H2 and CO was obtained at 50 kPa

    Rheology and Stability Mechanism of Water-in-crude Oil Emulsions Stabilized by Span 83

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    Water-in-crude oil (W/O) emulsions are found in many industries such as cosmetic, pharmaceutical, and petroleum. The study was aimed to investigate the rheological properties and the stability mechanism of W/O emulsions at different water to oil ratios of (20-80 vol.%) and (40-60 vol.%). The emulsions were stabilized by a non-ionic surfactant (Span 83) at concentrations of 1.5-2.5 vol.%. The heavy and light crude oils were mixed at 50-50 vol.% and characterized in terms of physical and chemical properties. From the results, it was found that the emulsion with higher water volume fraction obtained more viscosity with larger droplet sizes which present low stability. As well as, the higher viscosity was obtained in emulsion with higher emulsifier concentration (2.5 vol.%). However, 20-80 % W/O emulsion and emulsions stabilized with 2.5 % Span 83 produced more stable emulsions as observed through the optical microscopy images. In order to determine the dynamic viscosity, different temperatures from (30 to 90 ºC) and spindle rotational speeds from (50 to 250 rpm) were used. Furthermore, all types of prepared emulsions were visually stable over a period of more than one week, where no water separation was observed during this period, besides; they exhibited a non- Newtonian shear thinning fluid behavior

    A Short Review on Mesoporous Silica-Supported Catalysts for Methane Dry Reforming

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    The aim of this review is to gain a better insight in to the recent developments made in mesoporous silica molecular sieves, such as MCM-41, SBA-15, and SBA-16, as supports for dry reforming of methane. It further explored how different constraints such as the synthesis method for the mesoporous materials and techniques for metal loading on the mesoporous materials influence the dry reforming reactions and products yields. The high surface area and 2D hexagonal arrays of MCM-41 and SBA-15, 3D cage like structure of SBA-16 allow for good dispersion of metals inside their channels, which in turn, facilitates high catalytic activity and less catalyst deactivation. In this review, attention will be given to different strategies for enhancing catalytic activities, and the effect of metal dispersion on mesoporous silica supports

    Ethanol CO2 Reforming over Cu/Al2O3 Catalyst for Syngas Production

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    ethanol CO2 reforming (ECR) over 10%Cu/Al2O3 catalyst was investigated for production of syngas. The catalyst was synthesized by implemented incipient wetness impregnation method and characterized by using X-ray diffraction (XRD). ECR was evaluated in a stainless steel fixed-bed reactor by varying reaction temperature from 973 K to 1023 K. XRD analysis indicated the formation of CuO phases and eventually reduce to Cu metallic during H2 reduction. The ethanol and carbon dioxide conversion reached until 55.39% and 38.91% respectively at 1023 K reaction temperature. Furthermore, H2/CO ratio was obtained below 2 which is ideal for Fisher-Tropsch synthesis (FTS)
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